This invention relates generally to exercise equipment. More specifically, the invention relates to an exercise device wherein a user""s foot travels in an elliptical path of travel.
Because of a growing appreciation for the benefits of regular exercise; and because constraints of time and space prevent many persons from indulging in activities such as running, swimming and walking, the market for exercise equipment is rapidly increasing. It is generally desirable to exercise a number of different muscles over a fairly large range of motion so as to provide for even physical development and a maximum level of aerobic exercise. It is further desirable that exercise equipment provide a smooth, relatively natural motion so as to avoid jarring or irregular strains which can damage muscles and joints. It is also desirable that exercise equipment be relatively easy to use and of simple, low cost construction. While a number of different exercise systems are known in the prior art, such systems suffer from a number of shortcomings which limit their utility. Stationary bicycles are widely used; however, they are employed in a sitting position and consequently, the number of muscles exercised is small. Furthermore, the range of motion provided by a stationary bicycle is fairly limited. Stationary devices for simulating cross country skiing are also in widespread use. While these systems exercise more muscles than do stationary bicycles, the relatively flat, shuffling foot motion provided thereby does not adequately exercise all of the leg muscles through a wide range of motion. Stair climbing equipment also exercises more muscles than do stationary bicycles; however, the rather limited up and down motion provided thereby does not exercise leg muscles through a large range of motion. Treadmills and the like permit walking or jogging in a relatively limited area; however, they can be quite jarring to knee and ankle joints, and many users find it difficult to maintain balance on a treadmill.
The inventor of the present invention has previously recognized that a very beneficial form of exercise, which is simulative of a combined running and stepping motion, is achieved when a user""s foot is made to travel along an elliptical path. This mode of exercise provides a non-jarring action which is very comfortable and exercises a user""s muscles through a wide range of motion. In a most preferred mode of operation, a user""s foot travels in a back and forth elliptical path wherein, on the forward portion of the motion, the user""s heel initially rises at a faster rate than does the toe; while on the rearward portion of the cycle, the user""s heel initially falls at a faster rate than does the toe. This elliptical action, and most specifically the preferred action, provides a pleasing motion which may be sustained through a full aerobic workout. In combined psychological and physiological tests, users have reported that the perceived effort required to burn a fixed number of calories is lower when elliptical mode exercisers are used, as compared to perceived effort required to burn the same number of calories when using other exercise devices such as stair steppers. Exercise devices which achieve an elliptical foot action are disclosed in U.S. Pat. Nos. 5,243,343; 5,383,829; 5,518,473; 5,755,642; 5,788,609; 5,577,985; 5,611,756 and 5,911,649 among others. While the foregoing patents all describe apparatus for achieving an elliptical action, still other mechanical systems may be configured toward that end. Accordingly, and as will be described in detail hereinbelow, the present invention is directed to yet other novel configurations of elliptical exercise apparatus.
There is disclosed herein an exercise device comprising a frame configured to be supported on a floor and having a first pivot axis defined thereupon. The apparatus further includes a first and a second crank arm, each crank arm is pivotally attached to the frame at a first pivot axis so as to be rotatable thereabout. The apparatus also includes a first and a second drive link, and each drive link has a first, second and third attachment point defined thereupon. The first attachment point of each drive link is pivotally attached to a respective one of the crank arms so that the first attachment point of that drive link rotates about the first pivot axis. The apparatus further includes a first and a second guide member, each guide member is pivotally attached to a respective one of the drive links through a second attachment point thereof. The apparatus also includes a first and a second foot link, each having a first and a second connection point defined thereupon. Each foot link is pivotally connected to a respective guide member through its first connection point. The apparatus also includes a first and a second control link, each of which is pivotally connected to a respective drive link through the third attachment point thereof, and to a respective foot link through the second connection point thereof. In operation, the guide members reciprocate back and forth, and the control links are operative to vary an angle defined between the guide members and their associated foot link as a function of the reciprocal motion of the guide members. This causes the foot of a user which is disposed on the foot link to travel in an elliptical path.
In specific embodiments of the invention, the guide members comprise roller assemblies which most preferably reciprocate along one or more tracks supported by the guide members. In other embodiments, the guide members comprise swing arms pivotally supported on the frame.